Squeeze the lemon in a bowl (remove the seeds), add all the sauce ingredients and blend until smooth and homogeneous.
Cook the Couscous, following the brand instructions.
The amount you use of sauce:couscous varies. We've had success mixing 6 parts of sauce with 4 parts of couscous, and 1 part sauce with 5 parts of couscous. Recommend trying the 1:5 sauce:couscous ratio first.